Water is an essential nutrient for human health. However, individuals may ignore drinking enough water due to the rush of everyday life. We present Grow, a conceptual smart bottle prototype designed to encourage users to drink water regularly. Our concept utilizes bottle surface as an ambient display instead of a traditional screen-based display to give feedback. Grow tracks daily water intake through an embedded liquid level sensor. It gives positive, abstract, non-intrusive and aesthetic feedback through heating up different parts of a thermo-chromic print on its surface (a tree image). We also present the results of a user study exploring 10 prospective users’ reactions to Grow as well as their expectations of smart water bottles in general.